Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen or sulfur. More rarely still, they may contain elements such as phosphorus, chlorine, and bromine.
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one methine group (=CH−) replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated polymeric chains, which show significant electrical conductivity. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Historically, pyridine was produced from coal tar. As of 2016, it is synthesized on the scale of about 20,000 tons per year worldwide.
Acridine is an organic compound and a nitrogen heterocycle with the formula C13H9N. Acridines are substituted derivatives of the parent ring. It is a planar molecule that is structurally related to anthracene with one of the central CH groups replaced by nitrogen. Like the related molecules pyridine and quinoline, acridine is mildly basic. It is an almost colorless solid, which crystallizes in needles. There are few commercial applications of acridines; at one time acridine dyes were popular, but they are now relegated to niche applications, such as with acridine orange. The name is a reference to the acrid odour and acrid skin-irritating effect of the compound.
Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N. It is a colorless hygroscopic liquid with a strong odor. Aged samples, especially if exposed to light, become yellow and later brown. Quinoline is only slightly soluble in cold water but dissolves readily in hot water and most organic solvents. Quinoline itself has few applications, but many of its derivatives are useful in diverse applications. A prominent example is quinine, an alkaloid found in plants. Over 200 biologically active quinoline and quinazoline alkaloids are identified. 4-Hydroxy-2-alkylquinolines (HAQs) are involved in antibiotic resistance.
Diethyl malonate, also known as DEM, is the diethyl ester of malonic acid. It occurs naturally in grapes and strawberries as a colourless liquid with an apple-like odour, and is used in perfumes. It is also used to synthesize other compounds such as barbiturates, artificial flavourings, vitamin B1, and vitamin B6.
Hans Magnus Enzensberger was a German author, poet, translator, and editor. He also wrote under the pseudonyms Andreas Thalmayr, Elisabeth Ambras, Linda Quilt and Giorgio Pellizzi. Enzensberger was regarded as one of the literary founding figures of the Federal Republic of Germany and wrote more than 70 books, with works translated into 40 languages. He was one of the leading authors in Group 47, and influenced the 1968 West German student movement. He was awarded the Georg Büchner Prize and the Pour le Mérite, among many others.
Resorcinol (or resorcin) is a phenolic compound. It is an organic compound with the formula C6H4(OH)2. It is one of three isomeric benzenediols, the 1,3-isomer (or meta-isomer). Resorcinol crystallizes from benzene as colorless needles that are readily soluble in water, alcohol, and ether, but insoluble in chloroform and carbon disulfide.
Phosphoryl chloride is a colourless liquid with the formula POCl3. It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from phosphorus trichloride and oxygen or phosphorus pentoxide. It is mainly used to make phosphate esters such as tricresyl phosphate.
Isoxazolidine is the organic compound with the formula (CH2)3(NH)O. It is the parent of a family of compounds called Isoxazolidines, which are saturated C3NO heterocyclic rings where the nitrogen and oxygen occupy adjacent positions (1 and 2). They are the saturated analogues of Isoxazoles, and they are isomeric with oxazolidines, where the N and O are separated by one carbon.
Picolinic acid is an organic compound with the formula C
5H
4NCOOH). It is a derivative of pyridine with a carboxylic acid (COOH) substituent at the 2-position. It is an isomer of nicotinic acid and isonicotinic acid, which have the carboxyl side chain at the 3- and 4-positions, respectively. It is a white solid that is soluble in water.
Picoline refers to any of three isomers of methylpyridine (CH3C5H4N). They are all colorless liquids with a characteristic smell similar to that of pyridine. They are miscible with water and most organic solvents.
Dipicolinic acid is a chemical compound which plays a role in the heat resistance of bacterial endospores. It is also used to prepare dipicolinato ligated lanthanide and transition metal complexes for ion chromatography.
Pyridine-N-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis.
2,6-Pyridinedicarbothioic acid (PDTC) is an organosulfur compound that is produced by some bacteria. It functions as a siderophore, a small chelating agent with a high affinity for iron. Siderophores are deployed as ion scavengers for microbes. Siderophores solubilize compounds by forming strong complexes. PDTC is secreted by the soil bacteria Pseudomonas stutzeri and Pseudomonas putida.
Collidinic acid is an organic compound that belongs to the heterocycles. It belongs to the group of pyridinetricarboxylic acids and consists of a pyridine ring which carries three carboxy groups in the 2-, 4- and 6-positions. The name is derived from 2,4,6-collidine (2,4,6-trimethylpyridine).
Berberonic acid is an organic compound that belongs to the heterocycles. It belongs to the group of pyridinetricarboxylic acids and consists of a pyridine ring which carries three carboxy groups in the 2-, 4- and 5-positions. The name is derived from berberine.
Lutidinic acid is an heterocyclic organic compound, more precisely a heteroaromatic. It belongs to the group of pyridine dicarboxylic acids and consists of a pyridine ring which carries two carboxy groups in the 2- and 4-position.
Pyridinedicarboxylic acid is a group of organic compounds which are dicarboxylic derivatives of pyridine. Pyridinedicarboxylic acid comes in several isomers:
Diphenic acid, also known as Dibenzoic acid, is an organic compound with the formula (C6H4CO2H)2. It is the most studied of several isomeric dicarboxylic acids of biphenyl. It is a white solid that can be prepared in the laboratory from anthranilic acid via the diazonium salt. It is the product of the microbial action on phenanthrene.
Tetraiodine nonoxide is an iodine oxide with the chemical formula I4O9.
